Integration of MR (Magnetic Resonance) imaging and Linear Accelerators (LINAC) opens new horizons in Radiotherapy by improved lesion targeting, especially for moving organs. In a practical implementation proposal, the LINAC rotates around the subject to hit the gross target volume (GTV) and clinical target volume (CTV) from multiple angles while minimizing the radiation exposure for surrounding tissues. The combination of magnetic resonance apparatuses and LINAC radiotherapy sources is known.
The journal article Raaymakers et. al., “Integrated megavoltage portal imaging with a 1.5 T MRI linac,” Phys. Med. Biol. 56 (2011) N207-N214, doi:10.1088/0031-9155/56/19/N01 discloses the combination of a 1.5T MRI LINAC with a megavoltage portal imager.
EP2359905A1 describes a radiotherapy and imaging apparatus. The radiotherapy and imaging apparatus comprises a radiation detector, which can be used for QA and in-vivo dosimetry. The detector is positioned outside the magnetic coils mounted to the gantry, aligned with the radiation beam exit. It therefore has a fixed position relative to the radiation source.
US2010/0316259A1 describes a method for real-time 3D tracking of anatomical position during radiation therapy. To this end, during arc radiotherapy treatment, tomosynthetic images from projection images of an MV treatment beam are reconstructed.